<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        // var let const 共同点
        // var web = "baidu.com";
        // function show(){
        //     //私密空间可以调用外部的变量
        //     console.log(web);
        // }
        // show();
        // console.log(web);

        var web = "baidu.com";
        function show() {
            var web = "百度";
            console.log(web);
            function run() {
                console.log(web);
            }
            run()
        }
        show();
        console.log(web);
    </script>
</body>

</html>